PROJECT SUMMARY Over 15 million men and women provide informal caregiving services to family members who have dementia.1 The literature is replete with evidence that caregiving results in high rates of depression and distress,2 and potentially high rates of physical morbidity.3, 4 For example, 40% of caregivers are at risk for depression compared to just 5% of non-caregiving older adults.5 Further, increased symptoms of depression and distress in caregivers are associated with accelerated risk for developing cardiovascular disease.6 Thus, efficacious interventions for reducing caregiver distress appear potentially valuable for both mental and physical well-being. Given the distress experienced by caregivers, it is no surprise that over 80 intervention studies for reducing caregiver distress have been published.7 The message from these studies is that caregiver interventions, in general, are effective for reducing distress. Yet, the implementation of Evidence Based Treatments (EBTs) continues to be a challenge. Despite identification of EBTs, their use at the community-level has been absent. In 2007, NIH sponsored a workshop on the use of EBTs for caregivers. The conclusion was that ?The majority of effective interventions for caregivers were not being implemented through the aging network.?8 Ten years later, this lack of implementation remains. It is critical that scientists develop interventions for caregivers with maximal reach and minimal cost. Currently, most caregiver intervention frameworks require caregivers to meet with a therapist in one of four formats: a) face-to-face meetings with a therapist outside the caregiver's home, b) face-to-face meetings with a therapist in the caregiver's home, c) in-person, group-based meetings, or d) phone- based interventions in which caregivers call a therapist or support group. While possibly efficacious, these therapeutic formats are limited because: a) community agencies serving caregivers do not offer EBTs, b) the interventions are often not accessible to caregivers who reside outside the care network, c) they require caregivers to attend therapy sessions on specific days and times that may not be convenient for them, or d) they may require caregivers to find alternate care for their care recipients while they attend the therapy. To address these limitations, we have adapted an evidence-based, brief Behavioral Activation (BA) program to be delivered to caregivers via mobile phones with internet-based capabilities, thereby increasing caregivers' access to quality care. This mobile intervention has received positive feedback in feasibility testing, and we are now poised to conduct a full-scale trial of this intervention for improving key caregiver well-being outcomes. Further, we will test mechanisms of action, namely that increased behavioral activation promotes well-being in caregivers. To do so, we will recruit and randomize 200 caregivers to receive either a mobile BA intervention (N = 100) known as the mobile pleasant events program (mPEP), or a web-based bibliotherapy condition (N = 100) teaching skills on coping with caregiving. Participants will be assessed for depressive symptoms, positive and negative affect, well- being, and blood pressure at baseline, 3-months, 9-months, and 15-months follow-up time points.